Verification of short range thunderstorm forecasts using radar data to assess their benefit to the aviation community

On the afternoon of 20th July 1998 severe thunderstorms occurred over the south-east of England. It is understood that the airspace sector over that region had to be closed for safety reasons at fairly short notice. This caused severe disruption to air traffic. If severe thunderstorms can be forecast early enough, Air Traffic Management (ATM) authorities can, in future, take action to maintain safety levels, e.g. by re-routing aircraft to avoid the worst affected areas.

The aim of this study was to use radar data to verify short range thunderstorm forecasts produced by the Met. Office's GANDOLF (Generating Advanced Nowcasts for the Deployment of Operational Land-based Flood forecasts) system. The method of verifying the forecasts is intended to replicate the way in which the forecasts could be used in an aviation context. Specifically, both the forecast data and the radar data used to perform the verification are processed to calculate conditions under which an airspace sector might be closed. The output from this study consists of forecast accuracy statistics, which can be used by ATM authories to determine the value of the forecasts in the context of their own operations.